Eye diseases and disorders are prevalent, and if left untreated, many can lead to blindness. The four most common eye diseases are glaucoma, cataracts, diabetic retinopathy, and macular degeneration.
In a healthy eye, fluid within the aqueous humor of the eye is regularly drained and replenished. But when a patient has glaucoma, fluid collects within the eyeball, and pressure builds up. Pressure can result in direct damage to the optic nerve, or it can restrict blood flow, which then indirectly injures the optic nerve. Such damage can cause blind spots, and if untreated, can lead to blindness.
The term "glaucoma” actually refers to a whole group of conditions, all of which result in pressure inside the eyeball.
Symptoms of glaucoma include: blurred vision, problems with night vision, light sensitivity, and loss of peripheral vision. It can be diagnosed with a tonometer, which measures eyeball pressure.
Risk factors for developing glaucoma include: age, race, family history, diabetes, and steroid use.
There is no cure for glaucoma, but its effects can be lessened with drugs that either decrease production of fluid in the eye, or increase the outflow of fluid. Surgery is also an option.
Cataracts involve cloudiness in the lens of the eye. Since light passes through the lens on its way to the retina, cataracts result in distorted vision. Cataracts are caused by chemical changes and thickening of the lens.
Symptoms are: blurred vision, double vision, poor night vision, and the need for bright light to accomplish close tasks. It is usually diagnosed in a standard eye examination.
Risk factors include age, UV ray exposure, cigarette smoking, and injury to the eye.
Cataracts may be surgically removed, and replaced with a clear plastic lens.
Diabetes takes a toll on many parts of the body, but the eyes are especially vulnerable. Damage to blood vessels in the eye can cause them to leak fluid into the retina. When new blood vessels form, they can cause blurred vision or even temporary blindness. Scar tissue is also a problem.
Symptoms may include: blurred vision, spots floating in the visual field, loss of vision, and poor night vision. It can be diagnosed with a routine eye exam.
Obviously, people with diabetes have the greatest risk; this is aggravated by obesity, high blood pressure, and pregnancy.
Treatment may involve laser photocoagulation, or surgery.
Although the exact cause of MD is not known, it's suspected that lifetime exposure to UV rays and damage done by free radicals are responsible for depleting the macular pigment.
Symptoms include: glare sensitivity, need for bright light to read or do close work, and, if unchecked, blind spots in the centre of the visual field. It is usually diagnosed in a routine eye exam, followed up by fluoroscein angiography.
Risk factors include: gender, age, eye colour, family history, and smoking.
Until recently, there was no effective treatment for "dry” macular degeneration, and only partly effective ones for the "wet” version. But new research has indicated that taking a combination of lutein, zeaxanthin, and meso-zeaxanthin (MZ), the substances that comprise the pigment, can help with regeneration of the pigment. This may reduce symptoms and halt the progression of the disease.
Regular eye examinations are key to early diagnosis of all four of the above conditions.